84 
PERMIAN BRECCIA OF LEICESTERSHIRE. 
Fkb., 1892. 
angular fragments of various lavas, generally resembling 
those already described. Some grains of haematite occur and 
one or two flakes of light-coloured mica. One of the quartz 
fragments contains minute enclosures arranged in a sort of 
honeycomb pattern. (120.) An angular piece of a grit from 
Stanton, containing a considerable number of rather irregular 
and unworn fragments of volcanic rock interspersed in a 
ferrite-stained matrix. The fragments are rather variable, 
sometimes containing well-marked felspar microliths, some¬ 
times small vesicles, but probably they belong to the andesite 
group. (3.) A rock interbanded with coarser and finer 
materials; the finer consisting chiefly of small pieces of 
felspar in a dusty, ferrite-stained matrix, the coarser of similar 
fragments with a considerable number of bits of Volcanic 
rock, some vesicular, some compact—in shape resembling the 
fragments in the specimen last described, and probably akin 
in species. (58.) One rock seems to consist of rather more 
basic material. It is fine-grained, greenish to purplish, with 
a thin, compact, greyish band. Under the microscope this 
finer-grained layer appears to be composed of a light brown, 
somewhat dusty-looking material, interspersed among tiny 
flakes of a greenish (? chloritic) mineral. In the coarser 
bands, the matrix has the same character, but is full of 
rounded grains (from about •006in. to -015in. diameter) of a 
rather darker brown and a dull green colour. Neither variety 
has much depolarising effect; both exhibit more or less of an 
aggregate structure, and probably are related to palagonite, 
especially the greenish form, and result from the decomposi¬ 
tion of basic volcanic glasses. A few grains of quartz of 
rather irregular outline are present in the slide. The rock is 
probably a Palaeozoic grit. (94.) From Measham, a very hard 
darkish-green, minutely-grained grit, containing apparently 
felspar and mica, besides quartz. (37.) A hard, fine-grained, 
greenish-grey, felspatliic grit with crystals of iron oxide, not 
improbably pseudomorphs after pyrite. Under the microscope 
it is seen to consist of small, rather angular fragments of 
quartz, earthy grains (doubtless decomposed felspar), a 
greenish mineral slightly dichroic, probably chlorite or altered 
biotite, a colourless mica, limonite and perhaps haematite, 
with a grain of tourmaline.* Probably a Palaeozoic rock. 
(60.) An excessively fine-grained, slightly felspathic quartzite, 
probably related to 48. The laminae appear to have been 
contorted by subsequent disturbance. (102.) A rounded 
pebble from a cutting at Woodville, near Boothorpe, of a 
* Two large boulders from the Coton Park and Linton Colliery 
(41, 40) are described later. 
